17 Must Haves When Building An Energy Efficient Home

Why build an ener­gy-effi­cient home? The answer is con­vinc­ing. An ener­gy-effi­cient home saves mon­ey by reduc­ing ener­gy use, pro­vides a high­er lev­el of com­fort to its occu­pants and increas­es the resale val­ue of the house. Ener­gy-effi­cient homes also fight against increas­ing green­house gas­es and glob­al warm­ing. Neg­a­tive impacts of glob­al warm­ing include ris­ing sea lev­els due to grow­ing rates of glacial melt­ing, more acidic oceans due to climb­ing car­bon diox­ide lev­els, and more fre­quent and severe weath­er events. For­tu­nate­ly, recent tech­no­log­i­cal advance­ments in build­ing mate­ri­als and con­struc­tion tech­niques make the process of build­ing an ener­gy-effi­cient home less chal­leng­ing. New home builders have many deci­sions to make when build­ing an ener­gy-effi­cient home; how­ev­er, most ener­gy-effi­cient homes have sev­er­al things in com­mon. An ener­gy-effi­cient home has a tight­ly sealed ther­mal enve­lope, con­trolled ven­ti­la­tion, high-effi­cien­cy heat­ing and cool­ing sys­tems, and ener­gy-effi­cient doors, win­dows, appli­ances, and home elec­tron­ics. The ulti­mate goal of an ener­gy-effi­cient home is to achieve net zero ener­gy use and cre­ate a com­fort­able home with high indoor envi­ron­men­tal qual­i­ty.

1. A Whole-Building System Approach for Designing an Energy-Efficient Home

The whole-build­ing sys­tem approach treats a home as one ener­gy sys­tem in which each part affects the per­for­mance of the whole-house. The whole-build­ing sys­tem approach makes effi­cient use of water, elec­tric­i­ty and oth­er nat­ur­al resources and strives to min­i­mize waste and mate­ri­als. It also ensures that all the build­ing pro­fes­sion­als are informed and under­stand every aspects that affect ener­gy use in the home. The goal of the whole-build­ing sys­tem approach is to cre­ate a home with low­er util­i­ty and main­te­nance costs, improved dura­bil­i­ty and com­fort, and a healthy and safe indoor envi­ron­ment. Archi­tects, con­trac­tors, and home­own­ers agree that design­ing an ener­gy-effi­cient home requires a whole-build­ing sys­tem approach.

2. Site and Room Orientation of an Energy-Efficient Home

Prop­er site ori­en­ta­tion (pas­sive solar design) of a home is essen­tial for tak­ing advan­tage of the sun’s ener­gy. Specif­i­cal­ly, in the North­ern Hemi­sphere homes should be ori­ent­ed north-south. The north-south ori­en­ta­tion min­i­mizes direct sun­light dur­ing the sum­mer (which lessens cool­ing demands) while max­i­miz­ing sun­light dur­ing the win­ter (which lessons heat­ing demands).

Room ori­en­ta­tion is also an impor­tant design con­sid­er­a­tion of an ener­gy-effi­cient home.

  • South fac­ing rooms have good sun most of the day and are ide­al for the main liv­ing spaces like liv­ing, fam­i­ly, and din­ing rooms.
  • East fac­ing rooms have good sun dur­ing the morn­ing and are cool in the late after­noon, which is great for kitchens and bed­rooms.
  • West fac­ing rooms get the late after­noon sun, which can be a prob­lem for kitchens and bed­rooms.
  • North fac­ing rooms have low lev­els of sun­light and are best suit­ed for ser­vice areas such as garages, laun­dries and bath­rooms.

3. Thermal Mass Materials of an Energy-Efficient Home

High ther­mal mass mate­ri­als are an impor­tant design ele­ment of an ener­gy-effi­cient home and typ­i­cal­ly used in walls and slab foun­da­tions. Ther­mal mass is the poten­tial of a mate­r­i­al to absorb and store heat ener­gy. High ther­mal mass mate­ri­als help sta­bi­lize tem­per­a­ture shifts with­in a home by slow­ing the rate of heat trans­fer. For exam­ple, at night an insu­lat­ed con­crete wall and floor will absorb the cool air and store it with­in its mass. Dur­ing the day, if the walls and floors are shad­ed, they will stay cool and so will the inte­ri­or of the home. In the win­ter, dur­ing day­light, the con­crete walls and floors absorbs the sun’s heat ener­gy. Dur­ing the night, the heat then slow­ly spreads through the wall and floor (con­duc­tiv­i­ty) and releas­es into the home. Water, stone, brick, and con­crete are exam­ples of mate­ri­als with high ther­mal mass. Steel, wood, and car­pet­ing are exam­ples of mate­ri­als with low ther­mal mass and should be avoid­ed as part of an ener­gy-effi­cient home design.

4. Continuous Insulation of an Energy-Efficient Home

An essen­tial design com­po­nent of an ener­gy-effi­cient home is con­tin­u­ous insu­la­tion (CI). In fact, the ASHRAE 90.1 and the Inter­na­tion­al Ener­gy Con­ser­va­tion Code (2015 IECC) require con­tin­u­ous insu­la­tion, which is defined by the ASHRAE Stan­dard 90.12013 as insu­la­tion that is uncom­pressed and con­tin­u­ous across all struc­tur­al mem­bers with­out ther­mal bridges oth­er than fas­ten­ers and ser­vice open­ings. A ther­mal bridge is a sec­tion of a wall assem­bly that allows heat and ener­gy to flow through it at a high­er rate than the sur­round­ing area and reduces the effec­tive R‑value1 of the wall assem­bly. The pur­pose of CI is to stop ther­mal bridg­ing, increase the effec­tive R‑value\ and elim­i­nate con­den­sa­tion. Con­tin­u­ous insu­la­tion stops air leak­age (ther­mal bridg­ing) in a home and saves home­own­ers mon­ey and ener­gy by reduc­ing mechan­i­cal ven­ti­la­tion costs and heat­ing and cool­ing expens­es.

5. Air and Moisture Barrier of an Energy-Efficient Home

Pre­vent­ing air and mois­ture infil­tra­tion to the inte­ri­or of a house is essen­tial to the design of an ener­gy-effi­cient home. Air tight­ness of a home is a crit­i­cal fac­tor in elim­i­nat­ing ther­mal bridges. Mois­ture resis­tance is cru­cial to pre­vent­ing rot and the growth of mold and mildew, which can sig­nif­i­cant­ly degrade the indoor envi­ron­men­tal qual­i­ty of a home. To min­i­mize air and mois­ture infil­tra­tion with­in a home, an air and mois­ture bar­ri­er, along with con­tin­u­ous insu­la­tion, is imper­a­tive to an ener­gy-effi­cient home design.

6. Bautex Wall System - Best Practice Towards an Energy-Efficient Home Design

Bau­tex Wall Sys­tem is a high ther­mal mass prod­uct that pro­vides con­tin­u­ous insu­la­tion and min­i­mizes air and mois­ture infil­tra­tion. The Bau­tex insu­lat­ed con­crete blocks pro­vide an R‑14 con­tin­u­ous insu­la­tion that meets, if not sur­pass­es, the codes and stan­dards of the (ASHRAE 90.1) Code (2015 IECC). Also, appli­ca­tion of the Bau­tex AMB 20 air and mois­ture bar­ri­er to the Bau­tex Block wall cre­ates a mois­ture resis­tant, air­tight home that elim­i­nates ther­mal bridges and con­den­sa­tion.

In addi­tion, the Bau­tex Wall Sys­tem is noise reduc­ing, easy to install, and dis­as­ter-resis­tant and has an ASTM E119 fire rat­ing of four hours with ASTM E84 val­ues for flame speed of zero and smoke devel­op­ment of twen­ty.

7. Cool Roofs of an Energy Efficient Home

A cool roof of an ener­gy-effi­cient home pro­tects against solar heat gain and keeps the house and attic space cool. Asphalt shin­gles, a tra­di­tion­al roof­ing mate­r­i­al, has a high ther­mal mass and will absorb the sun’s heat, which will trans­fer to the inside of a home. Typ­i­cal­ly, a cool roof is made of low ther­mal mass mate­ri­als like tiles, slate, or clay that are reflec­tive or have light col­ored pig­ments that reflect the sun­light. A won­der­ful cool roof option for homes with flat rooftops and lim­it­ed green space, is a green roof. Green roofs include any­thing from sim­ple plant cov­er to a work­ing gar­den. Cool roofs improve indoor com­fort and reduce ener­gy bills. They can also extend the roof’s ser­vice life.

8. Insulated and Waterproof Slab Foundation of an Energy-Efficient Home

Slab foun­da­tions are most effec­tive way to sep­a­rate an ener­gy-effi­cient home from the ground; sav­ing time, mon­ey, and mate­ri­als. Con­crete slabs, along with a con­tin­u­ous lay­er of rigid foam insu­la­tion under the slab, are per­fect for an ener­gy-effi­cient home design. The high ther­mal mass of con­crete holds radi­ant ener­gy and keeps a home warm and dry inside. Also, an acid-etched or dyed con­crete slab is a very attrac­tive fin­ished floor.

9. The Heating and Cooling System of an Energy-Efficient Home

A home’s heat­ing and cool­ing sys­tem account for 48 per­cent of a home’s ener­gy use. The design of an ener­gy-effi­cient home should con­sid­er high-effi­cien­cy heat­ing and cool­ing sys­tems that use less ener­gy. For exam­ple, the most effi­cient HVAC sys­tem is 95 per­cent effi­cient; mean­ing 5 per­cent of the ener­gy pro­duced is lost. It is imper­a­tive that HVAC pro­fes­sion­als install the sys­tems in accor­dance with ENER­GY STAR homes. Improp­er instal­la­tion of an HVAC lessens the effi­cien­cy of a sys­tem by up to 30 per­cent. VRF and vari­able speed HVAC sys­tems are some of the most effi­cient sys­tems avail­able.

10. Ventilation of an Energy-Efficient Home

Con­trol­ling ven­ti­la­tion of an ener­gy-effi­cient home is crit­i­cal because the air-tight­ness of an ener­gy-effi­cient home may trap pol­lu­tants (like radon, formalde­hyde, and volatile organ­ic com­pounds). It is essen­tial for an ener­gy-effi­cient home to install an ener­gy recov­ery ven­ti­la­tion sys­tem. An ener­gy recov­ery ven­ti­la­tion sys­tem con­trols ven­ti­la­tion and min­i­mizes ener­gy loss by trans­fer­ring ener­gy from con­di­tioned air going out to fresh incom­ing air. Oth­er use­ful meth­ods of ven­ti­la­tion for an ener­gy-effi­cient home are spot ven­ti­la­tion, such as exhaust fans in the kitchen and bath­rooms, along with nat­ur­al ven­ti­la­tion.

11. Glazing System of an Energy-Efficient Home

The win­dows, sky­lights and doors of an ener­gy effi­cient home pro­vide light, warmth, ven­ti­la­tion, along with ener­gy and cost sav­ings. Design of an ener­gy-effi­cient home should include ener­gy effi­cient win­dows, sky­lights, and doors appro­pri­ate to the home’s cli­mate zone. Also, in the north­ern hemi­sphere, major glaz­ing areas should face south to take advan­tage of the sun’s ener­gy in win­ter months when the sun is low. For warmer cli­mates, lim­it south fac­ing win­dows. If win­dows face south, install shad­ing devices can pre­vents exces­sive heat gain dur­ing the hot, sum­mer months.

12. Energy-Efficient Appliances

Design of an ener­gy-effi­cient home includes ener­gy-effi­cient appli­ances: wash­er and dry­er, refrig­er­a­tor, dish­wash­er, microwave, dehu­mid­i­fi­er, freez­er, etc. Ener­gy-effi­cient appli­ances reduce a home­’s ener­gy use, emit less air pol­lu­tion and increase the resale val­ue of a home. Select­ing ENER­GY STAR appli­ances ensure the prod­uct saves ener­gy and mon­ey and pro­tects the envi­ron­ment.

13. Energy-Efficient Home Electronics

The aver­age home owns 24 elec­tron­ic prod­ucts, which are respon­si­ble for 12 per­cent of a home’s elec­tric­i­ty use. In addi­tion in 2015, 24 per­cent of employed peo­ple did some or all of their work at home and require home office equip­ment. The design of an ener­gy-effi­cient home must include selec­tion of ENER­GY STAR®-labeled office equip­ment and elec­tron­ics.

14. Lighting of an Energy-Efficient Home

Light­ing con­tributes up to 15% of a home’s annu­al elec­tric­i­ty costs and is a cru­cial design con­sid­er­a­tion of an ener­gy-effi­cient home. Con­trols such as timers, pho­to­cells that turn lights off when not in use and dim­mers can save mon­ey and ener­gy. Exam­ples of ener­gy-effi­cient light­ing include light-emit­ting diodes (LEDs), com­pact flu­o­res­cent lamps (CFLs), and halo­gen incan­des­cent.

  • Light emit­ting diodes (LEDs) bulbs con­tain semi­con­duc­tors diodes that con­vert elec­tric­i­ty into light. LEDs are often used in recessed fix­tures, and small track lights, desk lamps, kitchen, under cab­i­net light­ing, and out­doors. LEDs are about 90 per­cent more effi­cient than incan­des­cent light bulbs; how­ev­er they are expen­sive, rang­ing from about $10 to $40. LEDs are the longest last­ing ener­gy-effi­cient bulb. LEDs last 50 times longer than a incan­des­cent, 20 – 25 times longer than a halo­gen, and 8 – 10 times longer than a CFL.
  • Com­pact flu­o­res­cent lamps are com­pact flu­o­res­cent light bulbs often used in recessed or can light­ing. They cost between $1.25 and $2.50 for a 60-watt-equiv­a­lent bulb. The CFL bulb burns cool and uses much less ener­gy than a tra­di­tion­al incan­des­cent bulb. How­ev­er, the cons of the CFL is it may take a minute or more to reach full bright­ness and CFLs con­tain a small amount of mer­cury, which makes recy­cling dif­fi­cult.
  • Halo­gen incan­des­cents have a cap­sule inside that holds gas around a fil­a­ment to increase bulb effi­cien­cy. They are are sim­i­lar to tra­di­tion­al incan­des­cent bulbs, but use less elec­tric­i­ty. Halo­gen are the least expen­sive ener­gy-effi­cient light­ing option at less than $1 each; how­ev­er, they do not have the longevi­ty of LED and some of CFL bulbs.

15. Water Heating of an Energy-Efficient Home

Water heat­ing accounts for 15 per­cent of ener­gy costs and is one of the largest ener­gy expens­es in a home. For­tu­nate­ly, there are sev­er­al high-effi­cien­cy water heater options that can save ener­gy and mon­ey: tan­k­less water heater, high-effi­cien­cy water heater, high-effi­cien­cy heat pump water heater, and high-effi­cien­cy solar water heater.

16. Energy-Efficient Home Design Includes Smart Home Devices

Includ­ing smarthome prod­ucts in the design of an ener­gy-effi­cient home is a con­ve­nient option for a home­own­er that saves mon­ey and ener­gy and makes a home safer. Exam­ples of smart home prod­ucts include pro­gram­ma­ble ther­mostats, occu­pan­cy or motion sen­sors, CO2 and oth­er air qual­i­ty alarms.

17. Renewable Energy Sources of an Energy-Efficient Home

The design of an ener­gy-effi­cient home should strive to cre­ate as much ener­gy as it uses by installing renew­able ener­gy mea­sures: for exam­ple, solar pho­to­volta­ic (PV) pan­els, wind sys­tem, small hybrid” elec­tric sys­tem, or micro­hy­dropow­er. Renew­able ener­gy sources can reduce or com­plete­ly elim­i­nate a home’s util­i­ty bills and may even have tax incen­tives.

The ulti­mate goal of an ener­gy-effi­cient home is to achieve net zero ener­gy use. The design should also strive to meet the Ener­gy Star require­ments for sus­tain­abil­i­ty, the Lead­er­ship in Ener­gy and Envi­ron­men­tal Design (LEED) stan­dards, and the Inter­na­tion­al Green Con­struc­tion Code (IgCC). Achiev­ing these stan­dards and require­ments will cre­ate an ener­gy-effi­cient home that saves mon­ey and ener­gy, cre­ates a high degree of com­fort for the occu­pants, and ulti­mate­ly increase the resale val­ue of the house. Vis­it Bau­tex Wall Sys­tem for more infor­ma­tion on must have ele­ments for design­ing an ener­gy-effi­cient home.

A build­ing’s wall assem­bly resis­tance to this flow is mea­sured by its effec­tive R‑value. The effec­tive R‑value includes all the mate­ri­als used in its con­struc­tion: the studs, sid­ing, dry­wall, fiber­glass batts, ply­wood or OSB sheath­ing, water con­trol plane. The high­er the R‑value, the less the con­duc­tiv­i­ties of the wall assem­bly.